The invention concerns an LCD-display panel.
LCD displays, in recent times, are being installed not only for small surfaced displays for use in PCs, measurement instruments and the like, but are being found in large panel displays such as are found in public transit services, in airports and in similar applications. In these cases, large surface LCD-display panels are made out of a multiplicity of LCD-modules set side by side and above one another. The single LCD-display module possess in each case, a plurality of single, controllable pixel elements. In order to be able to control these pixel elements, control circuits are assigned to each LCD-module. Such circuits are normally installed in the edge areas of the LCD-display module. LCD-display panels of this type have been disclosed by DE 296 07 786 U1. The individual LCD-display modules have been made known by DE 42 09 072 A1. However, if the display modules disclosed by DE 42 09 072 A1 are placed next to and above one another, then dark, inactive stripes appear in which no display is possible. In the case of the LCD-display panel of DE 296 07 786 U1 technology, the individual LCD-modules, however, were placed within a framework so that a cross-hatched pattern was formed. However, again, in the lines of the cross-hatching, no display could be made. Rather, what was optically created was an impression of a multiplicity of single displays located side by side and above and below one another.
Using as a starting point, the LCD-display panel disclosed by DE 296 07 786 U1, the present invention provides a composite LCD-display panel from a plurality of individual LCD-displays placed side by side and top and bottom from each other in which, between the individual LCD-display modules, nearly no passive surfaces remain.
Because of the fact that contiguous LCD-modules in the edge zones in which the control circuits are placed overlap in the manner of shingles, the control circuits can be covered over so that no passive surfaces continue to exist in the display surface. However, the control circuits cause dark shadows where the edge zones overlap. In order to prevent these dark shadows in the overlap zone, the two neighboring LCD-display modules in the overlap zone are not placed in immediate contact with one another, but exhibit a slight intervening distance therebetween and a backlight apparatus is utilized. Specifically, in the interstitial space so made, a light deflecting element, or an illuminating element, is placed. The light deflecting element, or the illuminating element, compensates for the shadowing of the backlight caused by the control circuits. In this way, in an observation of the LCD-display panel, no dark zones appear in the overlap areas. Thus, the backlight apparatus diverts ambient light through the LCD-display panel in accordance with this aspect of the invention.
In accord with an embodiment of the invention, any of the following can be installed as illuminating elements: micro-LEDs, organic LEDs, light emitting polymers (LEPs), or cold cathode fluorescent light emitters. The intensity of this illumination element is controlled such that the shadowing of the actual backlight is compensated for. Thus, upon observing the display, the overlap zone is not visible.
In accord with another embodiment, light can be deflected in the form of films with a microstructure such as via Fresnel lenses or micro prisms, or films with hologram structure can be employed. By such films, incident light falling in the lateral area of the overlap zone is redirected or re-radiated forward. Therefore, the second edge zone of the involved LCD-display module is lighted from the rear.
In accord with a further embodiment of the invention, the control circuits are placed in the first edge zone on a transparent carrying material. In this arrangement, the shadowing of the backlight apparatus by opaque elements, such as the control circuits, is reduced in the over-lapping area. In a similar advantageous aspect, the control circuits are embedded or encapsulated in a transparent matrix.
In another advantageous embodiment of the invention, the polarization filters employed in the LCD-display modules are not installedxe2x80x94as was the previous practicexe2x80x94up to the first edge zone. Rather, the polarization filters extend themselves principally over the active display surface; i.e., over the pixel elements of the respective LCD-display modules. Again, this measure reduces the darker areas and at least a portion of the backlight can diffuse through the conventionally used glass carrier in the polarization filter-free surfaces.
In a further advantageous embodiment of the invention, the individual LCD-display modules are tilted or inclined in relation to the general display surface. In this manner, the offset, which otherwise would be in evidence over the greater area because of the shingled arrangement, is compensated for.
In accord with yet another advantageous embodiment of the invention, square or quadrilateral shaped LCD-display modules are employed. In this aspect, the first and the second edge zones are designed to lie opposite one another. On the two other edge zones of the square or rectangle in which no control circuit is to be found, the LCD-display modules can be placed directly against one another by a joint such that a nearly contiguous transition contact is provided. This arrangement is to be found in the alignment described in DE-OS 100 23 378.3. To this stated DE-OS 100 23 378.3 is incorporated by reference.
As to further advantageous embodiments of the invention, the connection lines to the control circuits and to the illuminating element in the overlap areas are in the form of transparent, ribbon conductors. Accordingly, the shadowing of the backlight is diminished.